Caliper gauge



May 29, 192s.

A. STEINLE CALIPER GAUGE Filed Oct. 14, 1925 Patented May 29; 1928.

UNITED ASTATES PATENT OFFICE."

Anomi'srnmmi, or JENA, GERMANY, AssrGNon To 'mnrmm cAar. znrss, or JENA,

- GERMANY.

cALIriin GAUGE.

.Application led'otcber 14, 1925, Serial No. 62,374, and in Germany June a6, 1924.

Caliper gauges are already known which are provided with a movable-feeling member and a, part, `c lisplaceable.at an angle relaf tively to its direction of motion and acting upon an indicating Ydevice and, with which gauges an auxiliary body (e. g. a ball) serves for transmitting the displacement `of the feeling member to the. part actingupon the indicating device. Besides, caliper gauges have become known in' which suoli feelingmembers are used in pairs. However, all these .arrangements have the drawback that the measuring' pressure, which necessarily varies owing to the caliper gauge being guided by hand, impairs the indicating device.

possible to render insensitive a caliper gauge lof the kind in question to. the oscillations by the unequal distance of the parts of the surface from the axis of aboring to\ be measured, by arranging, the feelin members in such a way that the pair of fee ing mem- The present invention has for vits objectto4 obviate this drawback. It is bers is, movable inthe measuring directionV independently of the part 'connected tothe indicating device.

A particularlytsuitable construction of the caliper gauge in which this condition is satisfied is attained by modiying it in such', a way that the feeling membersare-delimited at the ends coacting with the saidjauxiliary the measuring head thereof. In Fig'. 3 is illustrated in a cross section the measuring head of a second caliper gauge serviiwfor the same purpose. The 'third example shown in Fig. 4,' partly in a cross section, represents a caliper gauge for Vmeasuring interior threads. yFig. 5 representsvin a view a constructional part of the third example.l

In the :first example there is supported in a measuringliead a a cylindrical bolt Z3, provided with a caliper pin 1 and having a lane endsurface b2. A Second cylindrical olt c, supported in the measuring head a and; having a caliper pin c1 and an oblique end surface c, is secured against rotation about itsa-xis bya screw d which engages bolts b and c-'are held inposition in the measuring head by a stop e, and. f respectively screwedin front of these bolts. Between their tw end surfaces b2 and c? lies a ball g bearing against the plane end surj kthe/cylindrical,body h by ,a rack k2 and a pinion il.' The measuring head a and thein- (li-eating device z' are screwed into a handle [i: havin a rough surface. On the measuring hea a are cast'two Supports a1 and a? into which are screwed pivots Z1 and Z24 re-` body, by surfaces, o-fwhich at least one isf inclined to the measuring direction and which bear against a ball by-which the displacement of the two feeling members relatively to each other is transmited to the part connected to the` indicating device. For obvious reasons it is necessary to. secure the feeling members terminating in an inclined surface against rotations about axes which are parallell to the measuring direction.`

The invention is disclosed by three confl 'structional examples shown in the accompanying drawing. Fig...1'shows, partly in a cross sectioi i,the elevation ofa caliper gauge according to the invention for measuring cylindrical'borings, Fig. 2 1s a top view of `spectivel each secured by a nut, in such a way t at its point of support lies on a circle whose diameter c`orresponds to the lower limit of the measuring range V"ot the calipergauge and. which is determined by the feeling oint of the caliper pin c1. y

Vhenv using the lcaliper gauge the two supporting pivots Z1 and Z2 must bear against tlieV wall of, the boring to be tested. A more or less strong pressure on both 0r one of the two pivots Z1 and Z2 cannot affectthe result o f measurement 'because the pins 'b1 and c1 always bear against the wall surface of the boringto be tested under the intluence'of the invariably acting power of the spring, straining the cylindrical body h.

l o n l l with its cylindrical end ina groove 0 3. Both s by screws o,A

In the second example there are supported in a measuring head mwhich, as in the first example, is assumed to be provided with two supports, two like caliper pins n with oblique end surfaces nl and secured against rotation which engage with their cylindrical ends in groovesvnz. tect the caliper pins against falling' out of the measuring head m there are provided twoA stops p. Against the two oblique end surfaces nl bears a ball g which, as in the first example, is acted upon by the spring, straining the cylindrical bodyI h.

In the third example a measuring headr, modified as a plug gauge and elongated by a tubular extension 1'1, is provided with a boring r2 which is continued in a boring 1'3.

These borings r2 and 1" receive a cylindrical body s which is longitudinally slit into two elastic partss1 and s2 and terminates in a spherical collar s3. The elastic parts s1 and s2 bear with surfaces s44 and 35 inclined to the longitudinal axis against a roller t, resting on a surface u1 of an end screw u, perpen-- dicular to the thread axis. The measuring head o" ispierced in two places opposite each other of a thread, which lies in a vplane containing the thread axis. The borings denoted by al and o2 receive caliper pins fw1 and wz, consisting of a cylindrical part, which is provided with a supporting-ball surface, and calipersball surface, both of which having the same center. The borings .1v1 "and 'v2 are shaped in such away as to allow the caliper pins w1 .and 'to2 to carry out small motions inthe measuring direction as well as in that direction perpendicularthere# threads,

to, which is parallel to the thread axis of the measuring head r. The supporting-ball surfaces of the caliper pins 'w1 and lw2 are kept by springs m with slots 061` .in permanent contact with plane surfaces s vand S7, whichv are `ground on the elastic parts sl'and s2 of i the'body s"y at the ends of these parts, prolever pin a,

jecting into the measuring head 0', parallel to the longitudinal axis of the measuring head. To the tubular extension r1 is screwed a handle y with rough surface., to which is again assumed to be fixed an indicating device z', the index of which being connected by a rack h2 and a pinion l with a caliperwhich is kept in contact by spring pressure with a spherical surface el with the body s.

The caliper gauge described as a third examplelis used for testing threads in the same way as one ofthe well-known plug gauges. However, 1t serves in addition for ascertaining by testing the flank diameters of single threads, irregularities within the thread, errors of thepitch and the like in `threads found correct when tested with the plug gauge. If, e. g. a single thread has turned out too large, the caliper pins 'w1 and In order to pro.

w2,`introduced into this thread, project with their caliper-ball surface beyond the pro- `iile of thread of the measuring head 7', and owing to the pressure of the caliper pin. .a against the roller t the two parts s1 and s2 are spread apart by a corresponding amount,

whereby the `flankdiaineter of the respece' tive part of the thread is always correctly indicated on the indicating device i because the caliper pins w1 and fw2 always bar i against the flanks with the same measuring ressure. Thereby, owing to the possibility of rotating thebody s about the sphericacollar s3, it isimmaterial whether both or only one of the caliper pins w1 and wz project beyond the profile of thread of the measuring head r. I f

Iclaim;

l. Caliper gauge, containing a casing, two feeling members supported in said casing substantially opposite each other and displaceable in the same straight line, a .member supported in `the said casing/displaceable approximately perpendicular to the direction of thedisplacement of the two feeling members, an indicating device containthe said member with the indicating device so as to impartI to the scale and the index a I relative 'displacement as the memberis displaced in the casing, and other means in said casing adapted to only impart to the said member a displacement in the casing if the feeling lmembers displace relatively to each other. V i

2. Caliper gauge for measuring interior containing a casing, two feeling members supported in said casing substantially opposite eachother and displa-ceable in the same straight line as well as in a direction perpendicular to Vthis-straight line, a member supported in the said casingdisplaceable approximately perpendicular to the direction of the displacement of the two feeling members, an indicating device containing a scale andan index, means for, coupling the said member with the indicating device so as to imp art to the scale and the index a relative displacement as the member is displaced in the casing, and other means in said casing adapted to only impart to the said member a displacement in `the casing if the feeling membersdisplace relatively to one another in the direction of the said straight line. Y

3. Caliper gauge forxmeasuring interior threads, containing a casing, the end of this l casmg carrying a thread, two feeling memin the said casing dis index, means for placeable approximateto the direction of the discoupling the with the indicating device so to the scale and the index a rela of the two feeling members, an device'containing a scale and an said member as to impart tive displacement as the member-'is displacedin the casing, and other means in said casing adapted to only impart to the said member a displacement in the casing if the feeling members displace direction of the said straight line.

ADOLF STEINLE.

relatively to one another in thel 

